The present invention relates to water sprinklers, and, more particularly, to water sprinklers which utilize an oscillating mechanism driven by the jet of water which issues from the sprinkler.
Step-by-step rotary or pulsating sprinklers of the impact type employ an impact arm mounted for oscillating movement about a vertical axis. The impact arm includes a drive spoon, which in an impact limiting position is disposed in a position to be engaged by the fluid stream issuing from the outlet nozzle of the sprinkler. The drive spoon includes an initial pull-in surface which engages the stream and, by virtue of such engagement, creates a reaction component in a direction to move the drive spoon further into the stream and away from the impact limiting position. The initial pull-in surface of the drive spoon serves to direct the stream engaging the same on to a spaced reactant surface which establishes a reactant force outwardly of the axis having a tangential component capable of effecting movement of the impact arm in a direction away from the impact limiting position. As the impact arm moves away, a helical torsion spring acting between the impact arm and the sprinkler body serves to retard the movement and effect a return movement of the impact arm to the impact-limiting position. When the impact arm reaches the impact limiting position with the drive spoon back in the stream, the arm impacts the rotatable sprinkler body so as to impart an arcuate movement to the sprinkler body mounted upright on the pivotal axis. In this way a relatively slow arcuate step-by-step movement is automatically cyclically imparted to the sprinkler body.
The helical torsion spring typically used for this purpose has its ends secured to the cooperating parts (that is, either the impact arm or the sprinkler body, depending upon the end) by threading the end through one or more apertures provided in the cooperating part and finally bending the tip about the cooperating part in such a manner as to preclude retreat of the spring end from the apertures through which it passed. As the spring ends must be bent during the assembly process, this procedure increases the cost of such assembly process. Furthermore, where the tips are bent either too far, so there is a tendency for the tip to break off in use, or not far enough, so the tip does not block passage through the apertures, retreat of the spring ends from the apertures is possible. Even where the spring tips are properly bent, the apertures through which the spring ends must pass are typically disposed in the cooperating parts so that the normal helical pattern of the spring is greatly deformed, especially the last turn or so at each end. See, for example, U.S. Pat. No. 3,977,610. This loss of uniformity in the disposition of the helical torsion spring is not only an aesthetic detraction, but more importantly introduces non-uniformities into the force with which the spring forces the impact arm against the sprinkler body at the impact limiting position, and, in extreme cases, can develop weakness in the spring after repeated use. Accordingly, the need remains for a sprinkler which utilizes a helical torsion spring having pre-formed ends which are easily engaged with the cooperating parts of the sprinkler during the assembly process by unskilled labor without further bending and without substantial distortion of the regular helical pattern of the torsion spring.
The trip mechanism used to automatically reverse the direction of rotation of a partial circle pulsating sprinkler typically includes latch means for interacting with the impact arm, trigger means for interacting with the sector stops (defining the limits of rotation) and a trip spring connecting the latch and trigger means. The ends of the trip spring are typically secured, one end to the latch means and one end to the trigger means, by bending of the spring ends during the assembly process or by the use of external fastening devices. The bending during the assembly process introduces many of the same problems involved with the bending of the helical torsion spring during the assembly process, while the use of external fasteners add to the manufacturing costs as well as requiring additional steps in the assembly process. Accordingly, the need remains for a sprinkler having a trip spring with pre-bent ends adapted for ready engagement with the cooperating parts during the assembly process without the need for further bending of the trip spring ends and without the need for any external fasteners.
In partial circle sprinklers, the bushing-mounted sector stops used to define the limits of rotation typically do not totally extend around a circumference of the bushing. Where the sector stop is made of strongly resilient material, such as metal, and the circumferential portion of the bushing is smooth, a single radially extending tab can be provided on the sector stop as the sector stop can be rotated usually only in one direction by pushing the tab. The friction between the bushing and the sector stop suffice to hinder unintended sector stop rotation. On the other hand, where the sector stop is formed of a less resilient material, such as plastic, the bushing member typically includes a circumferential portion defining radially projecting ridges and each of the sector stops has adjacent each end thereof a radially inwardly projecting lug adapted for meshing engagement with the bushing ridges to preclude sector stop rotation in both directions. Pressure against one of the sector stop ends releases the associated lug from engagement with the bushing ridges and permits the rotation of the sector stop in a first direction (but not a second), while pressure against the other sector stop end releases the associated lug from engagement with the bushing ridges and permits rotation of the sector stop in the second direction (but not the first). Thus, in order to fine tune the positioning of a sector stop, the user may have to resort to grasping in turn one end, then the other, of the sector stop. Thus the need remains for a plastic sector stop useful with such a ridged bushing, but having a single tab by means of which one may rotate the sector stop in either direction. The single tabs facilitate accurate setting of the desired arc between tabs, avoiding the confusion inherent in the use of four sector stop ends.
In a partial circle pulsating sprinkler, the sprinkler slowly rotates in a step-by-step mode through the desired arc of rotation defined by the sector stops, the slowness of the rotation enabling the full potential range of the spray to be achieved. When the trigger means of the trip means encounters the sector stop at the end of the arc, the trigger means is moved, the trip mechanism is tripped, and the latch means is displaced so as to cause a rapid step-by-step counter-rotation by the sprinkler body back to the extreme other end of the arc. There the interaction of the trigger means with the other sector stop again trips the trip mechanism and reverses the rotation of the sprinkler body back to the desired direction of slow rotation. When it is desired to operate a partial circle sprinkler in a full circle mode of operation, a portion of the trigger means is simply folded out of the way so that the trigger means either does not contact the sector stops or at least does not contact them in such a way as to cause tripping of the trip means. In those instances where the trip mechanism just happens to be set for rotation in the sprinkler body in the direction of fast rotation, the sprinkler in full circle operation will rotate rapidly, thereby preventing the spray from reaching its full potential range. In this instance the user must shut down the fluid source or otherwise stop the initial rotation and then manually reposition the trigger means so that, when the fluid source is brought back up, the sprinkler body rotates in the desired direction of slow rotation. In many instances a novice user will not understand what has happened and will simply consider the sprinkler to be broken. Accordingly, the need remains for an automatic device within the sprinkler which, during full circle operation, automatically corrects the direction of rotation of the sprinkler body should the same prove necessary.
Accordingly, it is an object of the present invention to provide a pulsating sprinkler which utilizes a helical torsion spring having pre-bent ends which are easily engaged with the cooperating parts of the sprinkler during the assembly process without further bending, without the use of tools, and without substantial distortion of the regular helical pattern of the torsion spring.
Another object is to provide such a sprinkler which utilizes a trip spring with prebent ends which are easily engaged with the cooperating parts during the assembly process without further bending and without the use of external fasteners.
A further object is to provide such a sprinkler which employs a ridged bushing member and a pair of plastic sector stops, each sector stop having a single tab by means of which one may rotate the sector stop in either direction.
It is another object to provide such a sprinkler which is equipped with an automatic device which, during full circle operation, automatically corrects the initial direction of rotation of the sprinkler body should the same prove necessary.